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getting ph/hardness straight for diy co2

954 Views 7 Replies 4 Participants Last post by  Hoppy
I have a 29 gallon tank that until just recently I kept as sort of a walstad natural/low light tank, never did tests for anything and just did water changes once a month or every other month when I remembered to. The only thing I actually did for the plants was use flourish. I recently bought a new filter and light for the tank and want to do more stem plants/higher light plants and the light has 2 24 watt t5s which is kind of a lot of light I feel.

I want to start a diy co2 setup and I have everything ready except the water parameters. 2 weeks ago it tested at
ph 6.6ish
kh not even 1
gh 4

so I asked a guy I work with (I work at a lfs) about raising the kh to like 3 or 4. I'm also concerned that I don't have enough calcium in my water because in the past I've had a lot of plants give off twisted leaves which is either a calcium or co2 deficiency. I told him this and he gave me some of the store use reef builder, he said it'll raise the kh and shouldnt do anything to the ph. I put half a teaspoon in and then got strep throat and forgot to test the water.

anyways I just tested the water now and its at
ph 7.0
kh 1
gh 3
I'm not really sure what happened but I would like for the kh to be like 4 and the gh to be like 6, what can I do to fix this? also when I do water changes should I just change the water and then test it and adjust it to what I need?
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just found I have a bottle of equilibrium by seachem, says its for raising gh, raising the gh wouldn't necessarily raise the kh would it? and vice versa?
Why are you trying to jiggle around your kh and gh? If you think your plants have a nutrient deficiency (like calcium) you could probably address that more directly.
I've read in a couple places that you want a kh of at least 3 or 4 if you do co2 so your ph doesnt bounce around a lot, I've also read plants prefer a gh of 6-10. I thought I could get both of these in their proper ranges while addressing the possible calcium deficiency
also if those are totally wrong please let me know!
KH of anywhere above about 2 German degrees of hardness is just fine.
Baking soda is the most common material used to raise the KH.
1 teaspoon per 30 gallons will raise the KH by 2 German degrees of hardness, and will raise the pH a bit. Baking soda can be added directly to the tank, but I put it in right in front of the filter outlet so it dissolves best. It is OK if a bit lands on the floor of the tank, it will dissolve. You could also stir it into a glass of water and add that to the tank. It will be a little bit cloudy for a short time. Very short time, IME.
There is not a material that will raise KH without raising pH. Do not worry about pH.

GH is a measure of calcium and magnesium. If the GH of the tap water is under about 3 German degrees of hardness the water may be lacking one or the other, or both minerals. Can you get a water quality report from the water company? (Or are you on a well?)
You can add GH booster, a blend of Ca and Mg. Equilibrium is one brand, and it also has potassium in it, and some trace minerals. All that is fine. This one will not affect the KH. This one is hard to dissolve. I shake it in a sealed jar of water, pour into the tank the milky water, then add more to keep dissolving more of it.

Another way to raise both GH and KH is to add coral sand, oyster shell grit or limestone sand to the filter. I use nylon stockings for this. These materials can raise all 3: GH, KH and pH.

A good recipe:
Make the GH what you want for the fish.
Make the KH about the same, plus of minus a degree or so.
Let the pH do what it wants.

If you are keeping black water fish, then filter the water through peat moss, or add Indian Almond Leaves or other materials that will add the organic acids that those fish like.

Most aquarium plants are not very picky about the mineral levels as long as they are not too low. GH and KH of 2-3 degrees is about as low as I would want for most average plants. There are some specialty plants that demand soft, acidic water. Carnivorous plants are one group, and there are others.
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thanks diana, I was using regular degrees hardness but I converted it to german degrees and it looks like my water is really really soft. the main concern I had about the hardness besides the possible calcium deficiency was the kh being too low for co2. I have checked the water report for my area btw and it just has things like lead and nitrogen concentration. I'm going to use baking soda and equilibrium to try and get the kh and gh to 4ish
You don't need to do anything to your KH or GH. About the only time GH is a problem is when your water has almost no magnesium in it. Then raising the GH with Epsom salt will correct that, or using a GH builder like Equilibrium will also do it. KH can be anything above 1, and possibly even lower, without causing any problems. Adding CO2 doesn't cause te pH to bounce up and down in any case, unless the KH is zero.

By far the biggest problem you now have, unless your light is a Coralife or FishNeedIt light, is too much light for you to easily avoid lots of algae problems. I suggest spending a lot of time studying how to run a high light tank before you use that much light.
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